Getting System.Net.Mail.MailMessage as a MemoryStream in .NET 4.5 beta

So, the below code used to work in .NET 4 to get a System.Net.Mail.MailMessage object as a MemoryStream, however with the release of .NET 4.5 beta a runtime exception occurs.

Assembly assembly = typeof(SmtpClient).Assembly;
Type mailWriterType = assembly.GetType("System.Net.Mail.MailWriter");
using (MemoryStream stream = new MemoryStream())
{
    ConstructorInfo mailWriterContructor = mailWriterType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(Stream) }, null);
    object mailWriter = mailWriterContructor.Invoke(new object[] { stream });
    MethodInfo sendMethod = typeof(MailMessage).GetMethod("Send", BindingFlags.Instance | BindingFlags.NonPublic);
    sendMethod.Invoke(message, BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { mailWriter, true }, null);

    .....
}

Runtime exception occurs on sendMethod.Invoke().

Solution 1:

Managed to figure out how to get this working again in .NET 4.5 beta. The private API Send() method in MailMessage has changed to: internal void Send(BaseWriter writer, bool sendEnvelope, bool allowUnicode)

Please find updated code below.

Assembly assembly = typeof(SmtpClient).Assembly;
Type mailWriterType = assembly.GetType("System.Net.Mail.MailWriter");
using (MemoryStream stream = new MemoryStream())
{
    ConstructorInfo mailWriterContructor = mailWriterType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(Stream) }, null);
    object mailWriter = mailWriterContructor.Invoke(new object[] { stream });
    MethodInfo sendMethod = typeof(MailMessage).GetMethod("Send", BindingFlags.Instance | BindingFlags.NonPublic);
    sendMethod.Invoke(message, BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { mailWriter, true, true }, null);

    .....
}

Solution 2:

This might be usable if you don't want to go with unsupported hacks and don't mind extra performance hit.

public static class MailMessageExtensions
    {
    public static string  RawMessage(this MailMessage m)
        {
        var smtpClient = new SmtpClient { DeliveryMethod = SmtpDeliveryMethod.SpecifiedPickupDirectory };

        using (var tempDir = new TemporaryDirectory())
            {
            smtpClient.PickupDirectoryLocation = tempDir.DirectoryPath;
            smtpClient.Send( m );
            var emlFile = Directory.GetFiles( smtpClient.PickupDirectoryLocation ).FirstOrDefault();
            if ( emlFile != null )
                {
                return File.ReadAllText( emlFile );
                }
            else
                return null;
            }
        return null;
        }

    }

class TemporaryDirectory : IDisposable
    {
    public TemporaryDirectory()
        {
        DirectoryPath = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
        Directory.CreateDirectory( DirectoryPath );
        }

    public string DirectoryPath { get; private set; }

    public void Dispose()
        {
        if ( Directory.Exists( DirectoryPath ) )
            Directory.Delete( DirectoryPath, true );
        }
    }

Solution 3:

for checking if extra boolean i use :

 If _sendMethod.GetParameters.Length = 2 Then
    _sendMethod.Invoke(Message, BindingFlags.Instance Or BindingFlags.NonPublic, Nothing, New Object() {_mailWriter, True}, Nothing)
 Else
    _sendMethod.Invoke(Message, BindingFlags.Instance Or BindingFlags.NonPublic, Nothing, New Object() {_mailWriter, True, True}, Nothing)
 End If